A conventional wheel is composed of a rim, a hub at the center of the rim and spokes connected between the rim and the hub. Each spoke has one end connected to the hub and the other end of the spoke extends through the rim and secured by a securing member.
The conventional rim includes multiple holes and the spokes each have a threaded section which extends through the hole, and the securing member has inner threads is securely connected to the threaded section to secure the spoke. By the spokes, the rim does not deform during use.
When securing the spokes, the spoke is inclined in the hole of the rim, or the hole is inclined for connecting the spoke. The securing way affects the force transmission of the spokes and relates to the performance of the spokes and the rim.
Taiwan Utility Patent No. 099204627 discloses a nut which is a hollow nut with a threaded section defined in the inner periphery of the passage thereof and has a cross-shaped outer appearance. The distal end of the nut includes continuous wave-shaped profile and a spherical portion is formed at the mediate portion of the nut. Multiple recesses are defined in the spherical portion and the front section of the nut is tapered. The nut is located in the hole of the rim and the distal end is threadedly connected to the threaded section of the spoke. The spherical portion is used to adjust the angle of the spoke and the rim and the recesses reinforce the connection.
Taiwan Utility Patent No. 099209270 discloses a rim with an inner rim and an outer rim, wherein the inner rim having walls extending radially therefrom, and the outer rim is fixed to the walls. The inner rim includes multiple holes and each hole has an axis which is inclined relative to the base surface of the inner wall. An opening is defined at the inner rim and located close to the outer rim. The inner rim includes a surface defined along the periphery of the opening and located around the hole. The axis of the hole is perpendicular to the surface.
The first example uses the spherical portion to adjust the angle between the spoke and the rim, and the recesses to secure the connection between the spoke and the rim. The second example provides an opening in the inner rim and the opening is inclined relative to the axis of the hole in the rim. The securing member is perpendicular to the hole so that the securing member is connected to the spoke at an angle. Another securing member can be connected to the spoke to further secure the spoke.
However, for the first example, there is a gap between the spoke and the hole in the rim so that when the wheel is in operation, the spoke shakes and could break or loose at the position where the nut is connected to the spoke. Therefore, the rim is easily deformed due to the loosened or broken spokes. For the second example, the opening is difficult to make and the inclination of the surface is fixed which restricts the position of the securing member. The securing member and the fixing member have the same threading direction which makes the spoke to be loosened easily.